Variable rate timer and programmer for firing machine guns



N. TASLITT April 22, 1958 VARIABLE RATE TIMER ANDPROGRAMMER FOR F I MACHINE cums Filed April 22. 1954 6 Sheets-Sheet l I FIGJ.

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nited States VARIABLE RATE TIMER AND PROGRAMMER FOR FIRING MACHINE GUNS Application April 22,1954,Serial No. 425,057

' 11 Claims. (Cl. s9 2e (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may bemanufactured and "used byor for the Government of the United States of? America for governmental purposes without the payment of royalties thereon or therefor,

The present invention relates to a variable rate timer and programmer for firing machine-guns and more particularly to a pulse generating electronic gun firing control device having a plurality. of adjustable pulse repetition frequency determining circuits and a programmer for. automaticaly selecting said determining circuits sequentially at predetermined intervals of time in accordance with a preset program of time intervals to fire a gun, or a bank of guns, through a preselected program of difiering rates of fire, determined by the sequence of said determining circuits, with a preset number of rounds at each-rate of fire, the preset number of rounds being determined by the preset program of time intervals. i

In the prior art, gun firing control systems have been devised wherein solenoidally operated machine-guns or electric primed machine-guns are fired in synchronic response to electric impulses from impulse generating means. In .the electric primed type of machine-gun, a cartridge having an electric primer is tired by conducting an electricimpulse or a high voltage charge, such as the discharge of a condenser or the buildup of induced voltage in the secondary coil of a transformer, to the In the solenoidally operated type of machine-gun, a solenoid is provided to fire the gun upon energization thereof in response to an electric impulse or high voltage charge.

Also, it has been proposed to fire guns of the aforementioned types by utilizing electro-mechanical means to intermittently close the circuit providing the energizing potental to the gun firing actuating means. Generally,

' such electromechanical means comprise an electric current source for providing the energizing potential for the gun firing actuating means and switching means including a distributor having a fixed contact or a plurality of fixed contacts, depending upon the number of guns desired to be tired, disposed on its periphery and a rotatable contact fixed contacts, in the case of the electro-mechanical firing means, and the repetition rate of the impulses, in the case of the impulse generating means. These prior art gun firing devices have no provisions for varying the rate of fire and are not adaptable to selectively fire a gun at aten differ-in" rates of fire nor is their construction sufficientl versatile as to be adaptable to incorporate selective means for selectably and expeditiously changing the rate of fire of a gun. Furthermore, none of these prior art gun firing devices has automatic provisions for sequentially firing a machine-gun through a preselected program of different rates of fire with a preset number of rounds at each rate of fire.

The present invention is directed to an improved gun control firing device wherein manual selective means are provided whereby the rate of fire of a gun may be selectively and discretionally varied and wherein automatic means are provided to successively vary the rate of fire of a gun at predetermined intervals of time in accordance with a preset program of time intervals whereby a gun may be automatically fired through a preselected program of rates of fire with a preset number of rounds at each rate of fire, and wherein selective means are provided to adapt the gun firing device for either manual or automatic operation.

An object of the present invention is to provide a gun firing control system capable of firing either an electric primed machine-gun or a solenoidally operated machine-gun. l

Another object of the present invention is the provision of a gun-firing control device having means for selectively varying the rate of fire of a gun.

Still another object is to provide a gun firing control device including a variable rate timer having selective means for varying the rate of fire of a gun.

Another object is to provide a gun firing control device including a pulse generator for firing a gun, or a bank of guns, in synchronism with the pulse output thereof and having means for varying the pulse repetition frequency of said pulse generator to thereby vary the rate of fire of said gun, or said bank of guns.

A further object of the invention is the provision of a gun firing control device having means for sequentially varying the rate of fire of said gun in accordance with a preset program of rates of fire.

Another further object of the invention is the provision of a gun firing control device having means for successively varying the rate of fire of a gun at predetermined intervals of time in accordance with a preset program of rates of fire.

Another further object is to provide a gun firing control device having a variable rate timer with means for successively varying the rate of fire of a gun, or a bank of guns, at predetermined intervals of time in accordance with a preset program of timer rates to thereby change the rate of fire of a gun in accordance with a preselected program of rates of fire.

Another further object of the invention is to provide a gun firing control device including a pulse generator for firing a gun, or a bank of guns, in synchronism with the pulse output thereof and having means for successively varying the pulse repetition frequency of said generator at predetermined intervals of time in accordance with a preset program of pulse repetition frequency variations to thereby change the rate of fire of a gun in accordance with a preselected program of rates of fire.

A still further object of the present invention is the provision of a gun firing control device including means for sequentially varying therate of fire of a gun, or a bank of guns, in accordance with a preset program of rates of fire, and selective round control means for selectably determining the number of rounds to be fired at each rate of fire in a preset program of rates of fire.

Another further object is to provide a gun firing control device including a variable rate timer having means for successively varying the rate of fire of a gun, or a bank of guns, at predetermined intervals of time in accordance with a preset program of rates of fire, and having seleca.

tive round control means for selecting the number of rounds to be fired at each rate of fire in the preset program of rates of fire, said predetermined intervals of time being determined by the selected number of rounds to be fired at each rate of fire.

A still further object is to provide a gun firing control device including a pulse generator for firing a gun, or a bank'of guns, in synchronism with the pulse output thereof and having means for successively varying the pulse repetition frequency of said generator at predetermined intervals of time in accordance with a preset program of pulse repetition frequency variations, and selective round control means for selectively determining the number of pulses to be generated at each variation of said program of variations whereby the number of rounds to be fired at each rate of fire may be selected, said predetermined intervals of time being determined by the selected number of pulses to be generated at each variation of said program of variations.

A specific object of the invention isthe provision of "a gun firing control device including a variable rate timer 'vals of time in accordance with a preset sequence of time intervals to thereby selectably vary the rate of said timer through a preselected program of timer rates at a preset sequence of time intervals, and selective round control means for selecting the number of rounds to be fired at each rate of said program of timer rates, said predetermined intervals of time being determined by the selected number of rounds to be fired at each of the said timer rates.

A still another specific object is to provide a gun firing control device including a pulse generator for firing a gun, or a bank of guns, in synchronism with the pulse output thereof and having a plurality of adjustable discrete pulse repetition frequency determining circuits adaptable to be individually coupled to said generator, means for successively coupling individually said plurality of determining circuits to said generator at predetermined intervals of time in accordance with a preset program of pulse repetition frequency variations, and selective round control means for selecting the number of pulses to be generated at each variation of said program of variations whereby the number of rounds to be fired at each rate of .fire may be selected, said predetermined intervals of time being determined by the selected number of pulses to be generated at each variation of said program of variations.

In accordance with a primary object of the invention, there is provideda variable rate timer and programmer gun control firing system comprising a pulse generator for producing pulses to fire a gun in synchronism with the pulse output thereof at a rate of fire determined by the pulse repetition frequency of said generator; a first group 'of adjustable discrete pulse repetition frequency determining circuits; manual selective means adaptable to individually couple said determining circuits to said generator whereby the pulse repetition frequency of said .generator may be selectably varied; automatic means adaptable to vary the pulse repetition frequency of said generator at predetermined intervals of time and including a second group of adjustable discrete pulse repetition ferquency determining circuits adaptable to be individually coupled to said generator for predetermined durations of time in accordance with a preset program of time durations, a programmer for selecting the duration oftime each determining circuit of said second group is to be coupled to said generator, the selected duration of time of each determining circuit being determined by the number of pulses desired to be generated at each pulse repetition frequency and consequently determining the number of rounds to be fired at each rate of fire, and

relay operated step-switching means energizably operable in synchronic.response to the pulse output of said generator to individually couple the determining circuits of said second group succedently at predetermined intervals of time in accordance with the preset program of time durations to said generator and to render said automatic means inelfective after the completion of said preset program of time durations to thereby prevent cyclic recurrence of said preset program; and means for selectively coupling said manual means and said automatic means in circuit relation with said generator.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which like reference numerals designate like parts throughout the figures thereof and wherein:

Fig. 1 is a box diagram of the general concept of the invention;

Fig. 2 illustrates partly in box diagram and partly in schematic the preferred embodiment of the invention;

Figs. 3, 4, 5, 6a and 6b illustrate the schematic diagram of the preferred embodiment of the invention; I

Fig. 7 illustrates a box arrangement illustrating the interconnecting arrangement of Figures 3, 4, 5, 6a and 6b;

Fig. 8 illustrates the specific circuitry of the stepswitching relay means and reset circuit;

Fig. 9 is a view showing the mechanical features of the step-switch relay when in the de-energized position, ,and

Fig. 10- illustrates the mechanical features and position of the components of the step-switch relay when in the energized position.

In the several figures, all two position switches generally are illustrated as having an a position and a b position.

Referring now to the drawings, wherein like reference characters designate like or corresponding parts throughout the several figures, there is shown in Fig. l which illustrates, in box diagram, the general concept of the invention, an electronic gun firing system for firing machineguns and comprising a timer 1 of the pulse generator type, which may be one of many types of pulse generators known to those skilled in the art, for generating pulses at a rate determined by its pulse repetition frequency determining circuit, a manual pulse repetition frequency selector 5 having a plurality of adjustable pulse repetition frequency determining circuits, referred to hereinafter as P. R. F. determining circuits, indicated generally as f f and f and having a manually selective switch S3 adaptable to connect any one of the determining circuits to generator 1 when switch S1 is in the a position. Although three P. R. F. determining circuits are shown, it

is to be understood that any number of P. R. F. determin- 'ing circuits may be used. Each of the determining circuits f f and f is adjustable, as indicated by the arrows, to any frequency within the frequency range established by the parametric values of its respective components. The parametric values of the components in each P. R. F. determining circuit may be such that all the P. R. F. determining circuits may have the same frequency range or different frequency ranges.

A firing switch P8 of the push-button type is provided which, when in the depressed position, connects the output of the generator to a gun arrangement 2 which may consist of a bank of guns operable to fire a round simultaneously in synchronism with each pulse appearing in the output of the generator or may consist of two or more guns of different types, such as a solenoidally operated machine-gun and an electric primed machine-gun, adaptable to be singularly connected to the output of the generator so that either one or the other may be fired in response to the generator output. Firing switch FS, when depressed, also connects a portion of the generator output to switch S2. 0 r

Switches S1 and S2 are ganged for movement in unison and have two contact positions, namely position a and position b. When switch S2 is in the a position it is opencircuited, and when in the b position it connects the output of the pulse generator 1 to a step-switching system 3, to be hereinafter more fully described.

With switches-S1 and S2 in the a position, the gun firing system is in the manually controlled position, that is, the pulserepetition frequency of the pulse generator may be manually selectedand varied either by varying the frequency of any one of f1; fa. or i whichever is connected at the time to generator 1 through switch S3, or by switching S3 from one of the determining circuits to another which may be adjusted to a difierent frequency. For example, assuming that f f and i are 1 nected in circuit relation with generator I-through switch wiper S4. The contact positions 1, 2, 3, 4 represent the number of pulses that may be selected to be generated at the frequency of the determining circuit associated with its respective programming switch. Forexample, if it is desired to generate two pulses at the frequency of f selective member S is seton contact position 2 of protuned to widely different frequencies and switch S3 is connected to the contact of f generator 1 will produce pulses at the pulse repetition frequency as determined by h, and the guns 2, when firingswitch FS is in the depressed position, will fire a round in synchronism with each pulse at a rate of fire determined by the pulse repetition frequency of f Now if it is desired to slightly change the rate of fire, say from .35 rounds per minute to 38 rounds per minute, switchS3 is retained-in contact with h, and f is adjusted to attainthe desired 38 rounds per minute; but if it is desired to widely change the rate of fire, say from rounds per minute to'60 rounds per minute, then switch'S3 is manually moved to contact determining circuit f which may have been preadjusted to a pulse repetition frequency producing a rate of fire of 60 rounds per minute. Accordingly, therefore, a' gun firing system is provided, when switches S1 and SZ are in the a position, wherein the rate of fire of a niachine-gun, or machine-guns, may be manually varied at the discretion of the operator.

When switches S1 and S2'are in the 19 position, the gun firing system is converted to an automatically controlled firing rate condition of operation. tomatic condition of operation, switch S1 connects the. automatic P. R. F. selector 6 to generator 1 to determine the pulse repetition frequency of generator 1, and'S2connects the step-switching and reset system 3 to the output of generator 1. The automatic P. R. F. selector 6 has a plurality of adjustable P. R. F. determining circuits f f f and f and a movable switch wiper S4 adaptable In the an with its respective selective member.

to be actuated by a programmer 4, as indicated by the dotted line, to engage and connect f f f and f individually in succession to generator 1 at predetermined intervals of time in accordance with a preset program of time intervals as determined in programmer 4. Although the P. R. F. determining circuits of selector 6 are given dilferent reference characters from the P. R. F. determining circuits of selector 5, it is to be understood that the frequency ranges of P, R. F. selector 6 may be Within the same frequency ranges as 'P. R. F. selector 5. It is to be noted that upon throwing switch S1 in the b position, determining circuit f, is initially connected to generator 1. p

Programmer 4 has a programming switch for each of the P. R. F. determining circuits of selector 6, indicated generally as PS1, PS2, PS3, and PS4. The function of each programming switch is to determine the duration of time switch Wiper S4 retains its respective determining circuit in circuit relation with generator 1; that is, PS1 determines the period of time that switch wiper S4 retains determining circuit f connected to generator 1, PS2 determines the period of time switch wiper S4 retains f connected to generator 1, etc. Upon expiration of thetime duration set in programming switch PS1, switch S4 is actuated to connect f to generator 1. This process continues throughout the programming switches PS2 and PS3, and upon the expiration ofthe time duration set inprogramming switch PS1, as shown; if it is desired to generate three pulses at frequency f selective member S16 is set on contact position 3 of programming switch PS2;

etc. Since the contact positions are representative of the pulses generated, the preselected time duration of each determining circuit of selector 6 is determined by the numberof pulses desired to be generated at the frequency of .each determining circuit. It is to be understood that, although only five contact positions are shown, any number may be utilized. o

Also, each programming switch has a movable switch arm, indicated as 96, 97, 98 and 99, which is actuated by the step-switching system 3 to progressively move from one contact position to another in single steps in concurrence with each pulse at the output of generator 1 to ultimately contact its respective selective member at which instant switch wiper S4 is actuated to connect the succedent determining circuit in selector 6 tovthe generator. vWhen the movable switch arm engages its respective selective .member, it is rendered non-responsive to thestepswitching system by means to be described in conjunction with Fig. 2 and therefore remains in fixed engagement More specifically, with switch wiper S4 connected to f.,, generator 1 produces pulses at a pulse repetition frequency determined by 13,; upon generation of the first pulse and in response thereto,'step-switching system 3 moves movable switch arm 96 to contact position 1;.upon generation of the sec- -ond pulse and inresponse thereto, step-switching system 3 moves movable switch arm 96 to contact position 2to engage selective member S15 and remain in fixed. engagement therewith at which instant switch wiper S4 is actuated to connect 1,- in circuit with generator 1 to thereby enable generator 1 to produce pulses, at a pulse repetition frequency determined by f whereupon movable switch arm 97 is progressively actuated by step-switching system 3 in single steps in concurrence with each pulse produced by generator 3 at the pulse repetition frequency of f as explained for switch arm 96. This procedure is followed in sequence by movable switch arms 93 and 99.

The step-switching and reset system 3 includes a stepswitch, of the type illustrated in Fi s. 9 and 10 and to be hereinafter described, for each programming switch in programmer 4 and reset means for returning movable switch arms 96, 97, 98 and 99 to the home or contact position 0 which is the start position.

In order to automatically fire a machine un, or bank of machine-guns, through a preselected program of rates of fire, as determined by a preselected program of pulse repetition frequency variations, with a preset number of rounds at each rate of fire, as determined by a preset program of time intervals for the program of pulse repetition frequency variations, the operation of the automatic gun firing system is as follows:

The P. R. F. determining circuits f f f and are adjusted to frequencies corresponding to the rates of fire in the desired program of rates of fire. Adjustment of f f f and f7 presents a program of preselected pulse repetition frequency variations. Some ofthe P. R. F. de-

7 termining'circuits may be tuned to the same frequency, as for example, 1, and f may be adjusted to the same frequency; or, they may all be tuned to difieren't'frequencies. Time duration selective members S15, S16, S17, and S18 are set to the contact position corresponding to the number of rounds desired to be fired at each rate of fire thereby providing a preset program of time durations for the preselected program of pulse repetition frequency variations. For purpose of explanation, it is assumed that'the desired number of rounds at each rate of fire'are as shown by the settings of S15, S16, S17", and S18 in Fig. 1. Switches S1 and S2 are thrown to the b position and'the pulse generator 1 begins to produce pulses at the pulse repetition frequency as determined by f but, since firing switch FS has not as yet been depressed, the guns are not fired nor is the step-switching system operable to actuate the programmer and switch S4 through their respective programs. The system is now' ready to fire the guns upon depression of firing switch FS. When firing switch FS is depressed, the output of the pulse generator is connected to a gun (or a bank of guns, if so desired) to fire a round from the gun in synchronism with each pulse at a rate of fire determined by the pulse repetition frequency of f which is initially connected to generator 1. Upon the appearance, in the output of generator 1, of the first pulse at the frequency off the step-switching system 3 actuates switch arm 96 of programming switch PS1 to contact position 1, and upon the second pulse of f appearing in the generator output, switch 96 is again actuated by step-switching systern 3 to contact position 2 where it stops and engages S15 to actuate switch wiper S4 to connect f to generator 1. Thus, it is seen that the gun fires a preset number of rounds, specifically two rounds, at a rate of fire determined by the pulse repetition frequency of f As soon as switch wiper S4 connects f to generator 1, the generator develops pulses at the pulse repetition frequency of f and the gun is fired at a rate of fire determined by the pulse repetition frequency of f Swith arm 97 is actuated, as explained for switch arm 96, progressively in single steps in synchronic concurrence with each pulse appearing in the output of generator 1 to ultimately stop at contact position 3 and engage S16, whereupon switch wiper S4 is moved to connect i to generator 1 to thereby cause the generator to produce pulses at the pulse repetition frequency of f This procedure continues throughout the program until switch arm 99 stops at contact 3 to engage S18, at which instant the gun is rendered non-responsive to the generator output, by means to be more fully described hereinafter with regards to Fig. 2, and ceases firing, and the step-switching system is rendered inoperable, also by means to be described hereinafter with respect to Fig. .2. Upon cessation of firing of the gun, firing switch PS is released. Therefore, it is clear that the gun is fired through a program of variable rates of fire with a preset number of rounds being fired at each rate of fire. In order to fire another cycle of the program of rates of fire, it is necessary to return switch arms 96, 97, 98, and 99 to contact position 0, which is accomplished by actuating the reset system. The gun firing system is now ready to fire another program upon depression of firing switch PS.

In Figs. 9 and 10 is shown the structure of the type of step-switch utilized in step-switching system 3, Fig. 9 showing it in the de-energized position and Fig. 10 showing it in the energized position. The step-switch comprises a stepping magnet or relay, indicated generally as RL10, and includes a winding 70, an iron core 78a; an armature 71 pivotally mounted on pivot pin 69 and having a driving arm 75 with an insulated driver-72 integral therewith. Mounted on arm 75 is a spring 76 to which is riveted a driving pawl 77 engaging the teeth of a ratchet wheel 80 rotatably mounted on shaft 80a. A fixed supporting structure 79 has a retaining pawl 78 mounted thereon to prevent backward motion of ratchet wheel 80. There is also provided a fixed supporting structure 67 of insulating spacers to'hold three spring-leaf members 68, 34 and 66, member 68 having a contact 34b and member '34 having a contact 34a. Member 66 has an L-shaped portion '73 adaptable to be driven by driver 72, andmember '34 has an extended portion 74 adaptable to be driven by 73- to open contacts 34a and 34b. When coil 70 is de-energized, contacts 34a and 34b are closed, as shown in Fig. 9; and, when coil 70 is energized, armature 71 is attracted to iron core 70a and driver 72 drives "1'3, to: engage and push 74 rearwardly, opening contacts 34a and 341), as shown in Fig. 10. Also, as 71 is attracted to the iron core, spring member 76 permits driving pawl 77to engage a succeedingly counterclockwise tooth. Upon de-energization of coil 70, armature 71 is released and driving pawl 77 drives ratchet Wheel 80 in the clock wise direction a distance equivalent to one tooth. Although not shown in Figs. 9 and 10, contacts 34a and 34b serially connect an energizing source to the coil '70 through a push-button switch, which arrangement is shown in Figs. 6a and 6b, so that whenthe push-button closes the circuit armature 71 is attracted to the core 70a and driver 72 opens contacts 34a and 34b, de-energizing coil 70 and releasing armature 71 thereby enabling driver 77 to move ratchet wheel one step inthe clockwise direction. Upon contacts 34a and 34b closing, assuming the push-button is in the closed-circuit position, winding 7 0 is again energized and the procedure is repeated. From this operation, it is obvious that step-switch RLll) is of the self-interrupted type.

Referring now to "Fig. 2 which shows-the invention partly in box diagram and partly in schematic, there is shown a pulse generator 1 having an output circuit 7, and a normally open firing switch FS connecting the output 7 tolswitches S14 and S2.. Switch S14 is adapted to be selectively connected togun No. 1, which may be an electric primed gun or to gun No. 2 which may be a solenoidally operated gun as indicated 'by RL6. Connected to .the b terminal of switch S14 is a relay RL3 adaptable to be energized with each pulse appearing in output 7 to close the energizing circuit V3 of gun No. 2 thereby firing gun No. 2 in synchronism with the pulses appearing in output 7.

. In series with RL6 and V3 is a normally closed switch 42 adaptable to open the circuit of gun No. 2 upon energization of relay RL41 to thereby render gun No. 2 nonresponsive to the pulses in output 7. Connected in circuit with gun No. l isa normally closed switch 43 for opening the firing circuit of gun No. 1 upon energization of RL41. Also, if generator 1 is in a non-operating condition, a push-button FBI is provided whereby gun No. 2 may be fired at the discretion of the operator. Since gun No. l is of the, electric primed type, that is, having a cartridge with an electric primer, gun No. 1 will fire a round in synchonic response to the pulse output of output circuit 7, providing switch43 engages contact a. A switch S1, ganged to switch S2,'is selectively adapted to connect either a manual P. R. F. se'lect'orS or an automatic P. RcF. selector '6 to generator'I: The operation of the system when switch Slis in the manually operable condition is the same as described for Fig. 1.

The b terminal is connected to a sub-multiple sealer 8, which is optional, and to which is connected relay RL8, energizably operable in response to each pulse to attract armature 38 to its b contact. The purpose of sealer 8 is to reduce the number of pulses appearing in the output to a sub-multiple since the pulse repetition frequency of generator 1 may be so great that relay RL8 and the relays in stepswitching circuit 3 may be incapable of operating sufiiciently fast to be responsive to each pulse. If generator 1 is developing pulses at a low enough frequency, scaler 8 may be omitted. It is apparent from an analysis of the system that, when sealer 8 is connected in the system, gun No. 1 or gun No. 2 will fire a round in response to each pulse appearing in output 7 but relay RL8 will be energized only once for every two or more pulses, as

9 determined by scaler 8. For example, sealer 8 may be adjusted so that relay RL8 will be energized in response to every second or every fourih pulse appearing in output 7. Associated with relay RL8 is a switch 38 normally in contact with contact a which is open-circuited and adaptable to engage contact 1; upon energization of RL8.

Step-switching circuit 3, indicated generally as contained in a dash-dot box, includes a D. C. source V2 for energizing a plurality of step-switches, indicated as SS1, SS2, SS3, and SS4, of the type illustrated in Figs. 9 and 10. Each step switch has one side of its energizing circuit connected to the negative terminal -V2 of source V2. The other side of the energizing circuit of stepswitch SS1 is connected through lead 41 to contact a which, when relay RL11 is tie-energized, contacts arm-ature 11 which is connected to terminal +V2. Terminal +V2, when relay RL8 is energized 'by a pulse to attract switch armature 38 in engagement with its b contact, is connected to the positive side of source V2 through armature 38, contact b, line F, switch arm 41. and its contact a, and line G.

The other side of the energizing circuit of step-switch SS2, when relay RL21 is de-energized is connected through line 42 and contact a to armature 21 which is connected to the b contact of switch 11 through line 13. When relay RL11 is energized, armature 11 is attracted to its b contact, opening the energizing circuit of step-switch SS1 and closing the energizing circuit of step-switch SS2.

When relay RL21 is in the energized condition, armature 21 is drawn to engage its b contact, closing the energizing circuit of step-switch SS3 through lead 13, armature 31 and its a contact (RL31 being de-energized), and line 43. When RL31 is in the energized condition, armature 31 is pulled to its b contact, closing the energizing circuit for step-switch SS4 through line 44.

Included in the step-switching circuit is a source of power such, for example, as a 116 volt A. C. circuit, represented by the legend 119 AC, having one side of the line indicated as AC1 and the other side shown as AC2, for supplying the energizing potential for relays RL11, RL21, RL31 and RL41, each of which has one side of its winding connected directly to AC1 as illustrated by the arrow with the legend AC1 above it. The other side of the windings of relays RL11, RL21, RL31, and RIM-1 are connected through lines 81, 82, 83, and 36, respectively, to the On terminal of programming switches PS1,

PS2, PS3, and PS4, respectively. The AC2 side of the 110 volt A. C. source is connected to lines 101, 102,1ti3, and 104, of programming switches PS1, PS2, PS3, and PS4, respectively. When switch arm 96 of programming switch PS1 is progressively moved to contact position 2 by step-switch SS1, the energizing circuit for relay RLllt 'is completed from AC2 through switch arm 96, contact 2, time duration selective member S15, switch arm SE9, the On terminal, line 81, and winding of RL11 to AC1. The energizing circuits of relays RLZlt, RL31, and ELM are similarly traceable through programming switches PS2, PS3, and PS4, respectively. Relays RL11, RL21, RL31, and R1141 are adaptable to be succedently energized at predetermined intervals of time as determined by the presetting of selective members S15, S16, S17, and S18.

AC1 is also connected to armature 9 of relay RLll through line 33. The A. C. circuit through line 33 is normally open until relay RL11 is energized and draws armature 9 to its b contact, at which time the A. C. circuit is completed through line 12, armature 19 and its a contact, line 14, and the winding of relay RLB to the other side AC2 of the 110 volt source'to thereby energize relay RLB. Relay RL11 remains energized since movable switch arm 96 of switch PS1 is maintained at contact position 2. When relay RL21 is energized, armature 19 is pulled to engage its b contact thereby open ng the circuit of relay RLB and completing the energizing circuit for relay RLA through line 17, armature 29 and its a contact, line 22, and the winding of relay RLA to the other side AC2 of source AC. Relay RLZI remains energized and holds armature 19 in contact with contact b. When relay RLSZ is energized, armature 29 is drawn to its b contact position thereby opening the circuit of relay RLA and completing the energizing circuit for holding circuit 28 through lines 26 and 27, which holds relay RLA in an energized condition, and the energizing circuit for relay RLC through lines 26 and 34. When relay RL41 is energized, it draws armature 41 to its b contact and opens the circuit from V2 feeding D. C. current to the step-switches SS1, SS2, S83, and SS4 thereby rendering the step-switching circuit non responsive to the pulse output operating relay RL8, it also draws armatures 42 and 43 to their respective b contact positions to thereby disable guns Nos. 1 and 2 and render them non-responsive to the pulse output.

Also associated with the step-switching circuit is a reset circuit 3A including a push-button serially interconnecting the positive side of V2 through line B, stepswitches SS4, SS3, SS2, and SS1 to the negative side V2 of source V2. When push-button PBZ'is depressed, step-switches SS4, SS3, SS2, and SS1 will he returned to their initial starting position in the order named. The

step-switches in the reset circuit bearing legends SS1,

SS2, SS3, and SS4 are the same step-switches in the step-switching circuit bearing corresponding legends and are shown to be separate in order to facilitate the understanding of the system. Connected to the reset circuit is a reset indicator having a light L adaptable to be lit by D. C. source Vlwhen the step-switches are reset. The actual schematic circuit of the step-switching and reset system is illustrated in Fig. 8 and will hereinafter be more fully described.

The programmer 4 is the sameas described for Fig. 1 and includes the energizing network, as discussed for Fig. 1 but not shown in Fig. 1, for succedently energizing relays RL11, RL21, RL31, and R1441 at predetermined intervals of time in accordance with the preset program of selective members S15, S16, S17, and S18. The energizing network includes leads 191, 102, 103, and 1% connected to AC2 and energizing switches S19, S26 S21, and S22 which, when in the On position are connected to relays RL11, RL21, RL31, and RL41, respectively. When in the Off position, switches S19, S24), S21, and S22 are directly connected through lines 37 and 35 to relay RL41. If it is-desired to fire the gun through only three difierent rates of fire instead of four different rates of fire, energizing switches S19 and S21) are retained in the On position and S21 is thrown to the Off position to energize relay RL41 instead of RL31 after firing the gun at three different rates of fire whereupon relay RL41 disables the gun and renders the ste -switching circuit nonrespo-nsive to the pulse output. lfonly two difierent rates of fire are desired, energizing switch S20 is thrown to the Off position, or if only a short burst at the same rate is desired, energizing switch S19 is thrown to the Off position.

The automatic P. R. F. selector 6 includes a plurality of adjustable pulse repetition frequency determining circuits f f f and f adaptable to be successively coupled individually to the generator for durations of time as set in the programmer. Each determining circuit has a plurality of adjustable circuits i to f in 12;, i to fig in f f to f in i and f to flg in Each of these circuits may be adjustable within a specified range and may be alternatively selected by switches S23, S24, S25, and S26.

For example, f may be adjustable within the range of 15 to 24 pulses per minute, 3 within 25 to 34 pulses per minute, and f within 35 to 44 pulses per minute. Switch S23 may be thrown to connect any one of these to the generator. It is to be understood that the ranges stated are examples only and the invention is not to be construed to be limited to the mentioned ranges.

Although the means for successively coupling the determining circuits to the generator is shown to be a 1 1 wiper arm S4 in Fig. 1 for purpose of illustration, the means actually comprise relays RLB, RLA, and RLC, and holding circuit 28 to hold RLA in an energized condition when determining circuit is to be coupled to the generator.

Connected to the b terminal of switch S1 is armature 23 through line 24. Armature 23 engages its contact a, when RLA is de-energized, which is connected to armature 16 having contacts a and b. When RLB is deenergized, f, is connected to the generator, and when RLB is energized, is connected to the generator. Contact I) of armature 23 is connected to armature 65 of relay RLC which has contact positions a and b. When relay RLA is energized it draws armature 23 to its b contact and couplesf to the generator, assuming relay RLC to be deenergized. Now when relay RLC is energized, the holding circuit maintains relay RLA energized retaining armature 23in engagement with its contact b; also, energizetion of relay RLC attracts armature 65 to its contact b thereby coupling to the generator.

Operation of gun firing system of Fig. 2 For manual firing, switch S14 is thrown to either contact a or b, depending upon which gun is to be firedr Switch S3 is set to any one of f f or f;,, as desired.

Switches S1 and S2 are thrown to the a terminal, and firing switch FS is depressed to fire the selected gun at the selected rate of fire as determined by the frequency to which S3 is set.

For automatic firing, switches S23, S24, S25, and S26 in the P. R. F. selector 6 are adjusted to their desired positions to establish a preselected program of pulse repetition frequency variations. Time duration selective members S15, S16, S17, and S18 in programmer 4 are set to the number of pulses desired to be generated at each variation of the above mentioned program of variations and consequently determining the duration of time each pulse repetition frequency determining circuit is coupled to the generator, thereby establishing a preset program of time durations. It the complete range of the programmer is to be utilized, switches S19, S20, S21, and S22 are placed in the On position. Switches S1 and 52 are thrown to their respective b terminals, and generator 1 commences to'produce pulses at a frequency as determined in f Gun firing switch S14 is thrown to either a or b, as desired. In this condition, all relays are in the de-energized condition and the system is now ready to automatically fire a gun through a program of dilierent rates of fire with a preset number of rounds at each rate. For purpose of description, it is assumed that the desired number of rounds to be fired at each rate is as illustrated by the settings of selective members S15, S16, S17, and S18 in Fig. 2.

Upon depressing firing switch PS, the selected gun fires a round in synchronic response to each pulse appearing in output 7 at a rate of fire determined by the pulse repetition frequency of f Relay RLS is energized once for each pulse if sealer 8 is omitted, or is energized at a sub-multiple rate as determined by sealer 8 if it is conneeted in the circuit.

Each time relay RL8 is energized, it draws armature 38 to its contact b, closing the energizing circuit for stepswitch SS1 which in turn progressively moves switch arm 96 of programming switch PS1 one contact position for each pulse (assuming the sealer 8 has been omitted). When switch arm 96 is moved to contact position 2, the energizing circuit for relay RL11 is completed through S15, S19, On terminal, and line 81, and the gun has fired two rounds at a rate of fire determined by f.;. Upon relay RL11 being energized it simultaneously draws armatures 9 and 11 to their respective b contacts. When this occurs, the A. C. energizing circuit is completed for relay RLB in selector 6 from AC1 through-line 33, armature 9 and its b contact, line 12, armature 19 and its a contact, line 14, winding of relay RLB to AC2, and relay RLB draws armature 16 to its b contact thereby tie-coupling the 12,, determin- "12 ing circuit from the generator 1 and coupling determining circuit f to generator 1 whereupon generator 1 begins to produce pulses at a pulse repetition frequency determined by f At the same time, armature 11 having been simultaneously drawn to its b contact by relay RL11, the D. C. source V2 is removed from step-switch SS1, causing cessation of operation of step-switch SS1 and consequently cessation of progressive actuation of wiper arm 96 of programming switch PS1, and is applied to stepswitch SS2 through armature 11 and its b contact, line 13, armature 21 and its a contact, and line 42 through step-switch SS2 to the negative terminal -V2, resulting in energization of step-switch SS2 once for each pulse at the pulse repetition frequency as determined by i and resulting in firing the selected gun at a rate of fire as determined by i Meanwhile, since step-switch S81 is no longer actuating wiper arm 96 of programming switch PS1, wiper arm 96 remains at its contact position 2 to maintain relay RL11 in an energized condition.

As step-switch SS2 is energized in synchronic response to the pulse output, it progressively moves wiper arm 97 of programming switch PS2 one contact position per pulse until it engages contact position 3, at which instant the energizing circuit for relap RL21 is completed from AC2 through line 162, armature 97, contact position 3, selective member S16, switch S20, the On terminal, line 82, and winding of relay RL21 to AC1. Meanwhile, the gun has fired three rounds at a rate determined by i Upon relay RL21 being energized, armature 19 is disengaged from its a contact and drawn to its b contact, removing the A. C. source from relay RLB and applying it to relay RLA through armature 19 and its b contact, line 17, armature 29 and its a contact, line 22, line 95, and the winding of relay RLA to AC2 to de-couple f from generator 1 and couple f to generator 1 through armature 23 and its [2 contact, line 141, armature 65 and its a contact, and selecting switch arm $25 to the selected frequency of f whereupon the generator produces pulses at a frequency determined by f and the gun commences to fire at a rate of fire determined by f and, at the same time, armature 21 is disengaged from its a contact, removing the D. C. source from step-switch SS2 to thereby stop its actuation of wiper arm 97 of programming switch PS2 at contact position 3 to maintain relay RL21 in an energized condition, and is attracted to its b contact to close the D. C. energizing circuit for step-switch SS3 through armature 21 and its b contact, line 18, armature 31 and its a contact, line 43 through stepswitch SS3 to the negative terminal V2.

As step-switch SS3 is energized once per pulse through relay RLS at the frequency of f it progressively switches wiper arm 98 from one contact position to another in responsive concurrence with each pulse appear-ing in output 7 until wiper 98 reaches contact position 1 where it engages selective member S17 to close the energizing circuit of relay RL31 from AC2 through line 103, wiper arm 93, contact position 1, selective member S17, switch S21, the On terminal, lineSS, and through the winding of relay RL31 to AC1. Meanwhile, the gun has fired one round, as determined by the setting of programming switch PS3, at a rate of fire determined by the pulse repetition frequency of 1%,.

Upon being energized, relay RL31 opens the energizing circuit of relay RLA by breaking the contact of armature 29 with its a contact and attracting armature 29 to its b contact to permit energization of holding circuit 28 through lines 26 and 27 to hold relay RLA in an energized condition through lines 32 and thereby retaining armature 23 in engagement with its b contact; and, attraction of armature 29 to its b contact also closes the energizing circuit of relay RLC through armature 29 and its b contact, lines 26 and 34, and through the winding of relay RLC to AC2 to de-eouple f from generator 1 and couple ft; to generator 1 through armature 23 and its b contact, line 141, armature 65 and its b contact, and

13 selecting switch arm S26 to the selected frequency. Offq whereupon the generator produces pulses at a frequency determined by andthe gin commences to fire at a rate of fire determined by f Simultaneously with the attraction of armature 29 by relay RL31 to its b contact, armature 31 breaks contact with its a contact, removing the D. C. source from stepswitch SS3 to thereby stop its actuation of wiper arm 97 of programming switch PS3 at contact position 1 to maintain relayRLfal in an energized condition, and is attracted to its b contact to close the D. C. energizing circuit for step-switch SS4 through armature 31 and its [2 contact, line 44, and through step-switch SS4to the negative terminal -V2.

As step-switch SS4 is energized once per pulse through relay RL8 at the freguency of f it progressively moves wiper 99 of programming switch PS4 to successive contact positions in synchronisrnwith each pulse appearing in output 7 until wiper arm 98 reaches contact position 3 where it engages selective member 17 to close the energizing circuit of relay ELM from AC2 through line 104, wiper arm 99, contact position 3, selective member S18, switch S22, the On terminal, line 36, and through the winding of relay RL41 to AC1. Meanwhile, the gun has fired three rounds, as determined by the setting of programming switch PS4, at a rate of fire determined by the pulse repetition frequency of f When relay RLM is energized, it simultaneously draws armatures 41, 42, and 43 to their respective 1) contacts to open the firing circuits of guns Nos. 1 and 2 and rendering them non-responsive to the pulse output of output circuit 7 and to open the D. C. energizing circuit of the step-switching circuit thereby rendering the stepswitching circuit unoperative and non-responsive to the pulses of output 7. Since the step-switching circuit becomes unoperative when wiper arm 99 of programming switch PS4 engages contact position 3, wiper arm 99 remains in this position and relay RL41 remains in an energized condition. In this condition, the generator continues to produce pulses at the frequency of f but, due to the fact that both the guns and the step-switching circuit have been disconnected from the output 7, the pulses produced in the generator have no effect on the system. The firing switch PS may now be released.

It is to be understood that, although only four contact positions are shown for selective members S15, S16, S17, and S18, any number of contact positions may be utilized. Also, any number of pulse repetition frequency determining circuits, such as six or eight determining circuits instead of four as shown, may be utilized by simple modification of the system to accommodate the desired number of determining circuits.

Thus, it is clearly apparent that a gun is fired through a program of difi'erent rates of fire, as determined by a preselected program of pulse repetition frequency variations, with a preset number of rounds at each rate, as determined by the preset program of time intervals provided by the setting in the programmer of the number of pulses to be generated at each pulse repetition frequency.

In order to reset the step-switches to the start position, reference is now made to Fig. 8 which shows the specific circuitry of the step-switching circuit, the reset circuit, and the reset indicating circuit. The components are shown in the position attained after completion of the program, that is, with relays RL11, R121, 121.31, and RL41 in the. energized condition.

Step-switches SS1, SS2, SS3, and SS4 have a plurality of contact positions to 4, corresponding to the contact positions in programming switches PS1, PS2, PS3, and PS4 (Fig. 2), and a fifth contact position connected to switches S39, S40, S41, and S42 and indicated generally as contacts 180, 170, 160, and 150. Contacts 1 to 4 are serially connected for reasons to be subsequently described. Also, step-switche's' SS1, SS2, SS3, and SS4 14 have a movable wiper 87, 38, 89, and'90, respectively, which are ganged to wiper arms 96, 97, 98, and 99 (Fig. 2), respectively, to move in unison therewith. Each of step-switches SS1, SS2, SS3, and SS4 has a relay, indicated as RLlO, RL20, RLfitl, and R140, associated respectively therewith, which is of the type illustrated in Figs. 9 and 10, to actuate the wiper arms 87, 88, 89, and

in single steps, as shown by the ratchet wheel 80 and driving pawl 77 in Figs. 9 and 10, to succedent contact positions. Wiper arms 87, 88, 89, and 9! are shown to be stopped at contact positions corresponding to the contact positions wipers 96, 97, 98, and 99 arestopped at in Fig. 2 after completion of the program.

The system includes a first D. C. source V1 for supplying the energizing potential for the reset indicator circuits, and a second D. C. source V2 which has two circuit branches, namely, one through line G and the other through line E, for supplying the energizing potential for relays RL10, RLZO, RL30, and RL40. The legends G, F, and E are utilized to correspond with Figs. 6a and 6b, subsequently to be described.

The circuit branch through line G supplies an energizing impulse, as determined by the engagement of armature 38 with its contact b upon energization of relay RL8 by the pulse output 7, to relays RL10, RL20, RL30, and RL40, in the sequence permitted by relays RL11, RL21, and RL31 as described for Fig. 2. In tracing the circuit of the branch through line G, it is assumed that relays RL11, RL21, RL31, and RL41 are de-energized and their respective armatures are in engagement with their respective :1 contacts. The circuit to relay RL10 is completed from G through armature 41 and its a contact, line 3, armature 38 and its b contact (when relay RL8 is energized in response to the pulses in output 7), terminal +V2, armature 11 and its a contact, line 46, across contact aa of push-button PB3, line 49, and through winding 70 to the negative terminal -V2. of source V2. When relay RL11 is energized as described for Fig. 2, armature 11 engages its b contact to disconnect source V2 from relay RLIO and connect it across RL20 through armature 11 and its b contact, line 13, armature 21 and its a contact, line 51, across contacts a--a of push-button PB4, line 54, and through winding 70' to the negative terminal V2 of source V2. When relays RL21 and RL31 are energized, the energizing circuits for relays RL30 and RL40 may be similarly traced. And, upon energization of relay RL41, the circuit branch through line G is opened.

The circuit branch through line E supplies the energizing potential to relays RL10, RL20, RL30, and RL40 durlng the resetting operation. The circuit is' traced through line B, the serially connected contacts of stepswitch SS1, wiper arm 87, line 47, contact 34b, armature 34a, across terminals b-b of push-button PB3 when it is depressed, line 49, and through the winding 70 to the negative terminal V2. Upon depression of push-button PB3, relay RL10 is energized through thiscircuit and attracts armature 34a to break with 34b thereby opening the circuit and de-energizing relay RL10 which, upon de-energization thereof, releases armature 34a to engage contact 34b to complete the energizing circuit again. Thus, it is clear that relay RLlO is a self-interrupted relay. Upon each energization of relay RLM, wiper arm 37 is moved progressively to a succedent contact until it engages the fifth contact 180. Since contact is not connected in the circuit branch through line B, the reset energizing circuit of relay RL10 is opened and wiper arm 87 stops at contact 180.

The contact 0 and contact 180 are disposed along a circular arc and are 180 degrees apart. Although not shown, wiper arm 87 is composed of a straight conductive blade having a wiper contact at each end and having a pivot shaft equidistantly located from each end wiper contact for rotation thereabout so that, when one end wiper contact engages contact 180, the other end wiper contact engages contact 0. Therefore, when wiper 87 is stopped at contact 180, its opposite end wiper contact engages contact and is in the start position. The reset circuits of relays RL20, RL30, and RL40 operate the same way.

The reset indicator circuit includes a source VI for supplying a current to indicator lights L1, L2, L3, and

L4 and a plurality of manually operable switches S39,

Operation of reset circuit and reset indicator of Fig. 8

To reset the step-switching circuit after the completion of a program, as shown in Fig. 8, switch S42 is thrown to its b contact position and push-button PB6 is depressed to engage its bb contacts, whereupon relay RL40 operates self-interruptedly to move wiper arm 90 until it engages contact 150, at which time the energizing circuit for relay RL40 is opened and the lighting circuit for indicator light L4 is closed, lighting up light L4 to indicate that step-switch SS4 is reset. Switch S42 is then thrown back to its a contact position. This same procedure is followed for step-switches SS3, SS2, and SS1, in that order. After step-switch SS1 is reset, the system is again ready to fire another program.

Reference is now made to Figs. 3, 4, 5, 6a, and 6b, interconnected as shown in Fig. 7, which illustrates the complete schematic-circuit of the invention.

.Fig. 3 includes two voltage tripler power supplies, indicated generally as and 15, a multivibrator oscillater 20, a gas type trigger tube 25, a bank of relays RL1, RL2, RL3, RL4, a 110 volt A. C. source, and a firing switch-PS adaptable upon depression thereof to connect the A. C. source across the aforementioned bank of relays.

Power supply 10, which comprises selenium rectifiers in parallel and a filter network consisting of condensers C4, C5 and resistor R1, supplies power to the oscillator and trigger tube 25. Power supply 15, also composed of selenium rectifiers in parallel and a filter network of condensers C17, C18 and resistor R18, supplies power through lines W, X, and Y to the scalers and pulse amplifier 55 shown in Fig. 5. The required plate voltages are obtained by adjusting resistors R2 and R20;

A double-pole double-throw switch S5 is connected to one side of the oscillator 20, and a double-pole doublethrow switch S6 is connected to the other side of oscillator 20. A double-pole double-throw switch S7 is connected in the common cathode circuit of oscillator20. A switch S2 is connected to the output of trigger tube 25. Switches S5, S6, and S7 have a Manual position and an Automatic position to permit the frequency of the oscillator to be either manually varied or automatically varied, and switch S2 has a Manual position a to leave the output of trigger tube appearing across load resistor R8 open-circuited and an Automatic position b to connect the output across resistor R8 to the sealer circuit through line V.

The manually selected frequency determining circuits for one side of the oscillator comprise a bank CB1 of condensers C7, C8, C9, adaptable to be individually selected by switch S8, and a bank RB1 of resistors R11, R12, R13, individually selectable by switch S10; and the manually selected frequency determining circuits for the other side of the oscillator include a bank CB2 of condensers C10, C11, C12 having a selecting switch S9 and a bank R82 of resistors R14, R15, and R16 having a selecting switch S11. Switches S8 and S9 are ganged,

and switches S10 and S11 are ganged so that the frequency in both sides of the oscillator remains the same during the switching operation. A potentiometer R17 is provided to finely adjust the frequency of oscillator 20. When switches S5, S6, and S7 are in the Man position, the oscillatory frequency of oscillator 20 is determined by the selected condenser and resistor in the aforementioned banks of condensers and resistors and by the setting of resistor R17. Switches S8, S9, S10 and S11 are employed to vary the frequency in increments, whereas resistor R17 varies the frequency between the increments. When switches S5, S6, and S7 are turned to the Auto position, they connect the frequency determining circuits of the automatic P. R. F. selector to the oscillator through lines C, D, C, D, L, and L.

The output of the firing tube 25 appearing across resistor R19 at leads A and B is led directly to gun switch S12 in Fig. 4. The output of tube 25 appearing across load resistor R8 is led through the armature of relay RL1, switch S2 and its b terminal, and line V to the input of the scalers in Fig. 5.

Fig. 4 illustrates the gun firing circuit and includes a double-pole double-throw switch to which lines A and B are directly connected. When switch S12 is turned to the a position, it connects the output of the firing tube 25 to an electric-primed gun, indicated as gun No. 1, through the armature of relay RL3 and through a normally closed switch 42 in Fig. 6b connected to lines M and N, and, when switch S12 is thrown to its b position, the output of firing tube 25 is connected to a relay RLS through the armature of relay RL4 and through the normally closed switch 42 in Fig. 6b connected to lines M and N. As relay RLS is actuated by the pulse output of firing tube 25, it closes the D. C. circuit operating solenoidally operated gun No. 2. Push-button PBl feeds the D. C. directly to the gun solenoid RL6 and the gun will then fire at its automatic rate as long as push-button PBI remains depressed.

If it is desired to manually predetermine and vary the rate of fire of a gun, switch S12 is thrown to either its a or b position, as desired, switches S8, S9, S10, S11 are set at the desired oscillator frequency, switches S2, S5, S6, and S7 are turned to the Man position, and the firing switch is depressed, energizing relays RL1, RL2, RL3, and RL4 to close their respective armature thereby connecting the selected gun to the firing tube output to fire the gun at a rate of fire as determined by the pulse repetition frequency of the oscillator. If it is desired to change the rate of fire while the gun is firing, switches S8, S9, S10 and S11 are thrown to the next desired rate of fire.

In Fig. 5, the output of firing tube 25, when switch S2 is in the Auto position, is applied through line V to scaler No. 1 which comprises a double diode 30 and an Eccles-Jordan multivibrator 35. Sealers and Eccles- Jordan multivibrators, per se, are well known to those skilled in the art and require no further elaboration. A switch S13 is provided to connect, when in the a position, scaler No. 2 in cascade with sealer No. 1, or to connect, when in the b position, the output of sealer No. 1 directly to the input of tube 50 of the amplifier circuit. The amplifier circuit comprises a triode 50 and a pentode 55. The amplifier pulse output appearing across resistor R41 is applied to relay RLS (Fig. 6a) through the armature of relay RL2 and lines S and R.

The circuit incorporates the scalers in order to reduce the number of pulses fed to the step-switching circuit in Figs. 6a and 6b. The relays in the step-switching circuit will function reliably only up to about 250 pulses per minute. By using scalei' No. 1 alone, relay RL8 and the relays in the step-switching circuit will operate on every other pulse and areliable rate of 500 pulses per minute may be produced in the oscillator to fire the gun at a rate of 500 rounds per minute. By throwing switch S13 to its a position, scaler No. 1 and scaler No. 2 are employed and the reliable rate is 1000 pulses per -17 minute produced in the oscillator while relay RL8 and the step-switch relays are actuated by every fourth pulse. If the rate desired is sufliciently low, the scalers may be omitted, or if a greater rate is desired, additional scaler gayzbe connected in cascade with sealers No. 1 and In Figs. 6a and 6b are shown the step-switching circuits, the reset and reset indicator circuits, the programmer, and the automatic P. R. F, selector circuits comprising resistor-condensor networks RC1, RC2, RC3, and RC4. Lines S and R, connected to the output of the amplifier, feed the amplified pulses to a relay RLS having armatures 38 and 84. Connected to the b contact of armature S4 is a round counter 85 having compensating means to numerically compensate for the reduction in the number of pulses caused by the scalers. The circuit for the round counter is completed from lead H through normally closed switch 86 (Fig. 6b), lead K, armature 84 and its b contact.

Throughout Figs. 6a and 6b, leads terminating in arrows having a reference letter are connected to other leads terminating in arrows having a corresponding reference letter. Also, illustrated along the left margin of Fig. 6a are three voltage sources having legended arrowed leads which are connected to correspondingly legended arrowed leads in the schematic circuit shown in Figs, 6a and 6b;

The programmer comprises programming switches PS1, PS2, PS3, and PS4 having members S15, S16, S17, S18 selectively adjustable to any one of a plurality of contact positions 0 to 8 and having wiper arms 96, 97, 98 and 99 which are ganged to wiper arms 87, 88, 8 and 90, respectively, of step-switches SS1, SS2, SS3 and SS4, respectively. Connected to selective members S15, S16, S17, and S18 are isolating switches S19, S20, S21, and S22 respectively, which have an On and an Off position. For normal operation of the system in firing through the complete programming arrangement of four channels in the programmer, all of switches S19, S20, S21, and S22 are turned to the On positive thereby connecting relays RL11, RL21, RL31 and RL41 to selective members S15, S16, S17, and S18, respectively. When isolating switch S19 is thrown to the Off position, it connects selective member S15 to relay RL4 through lines 106 and 36. With isolating switch S20 in the OE position, selective member S16 is connected to relay RL41 through lines 107 and 36; and, with isolating switch S21 in the Oif position, selective member S17 is connected to relay RL41 through lines 108 and 36.

To fire less than a full program of four channels, RL41 is actuated by turning any one of switches S19, S20, and S21, depending on the number of channels desired to be fired through, to the Off position. The function of relay RL41 is to open the D. C.' energizing circuit through lines F and G of the step-switching circuit and to disconnect the pulse output through lines M and N from the gun selected by switch S12 (Fig. 4) when relay RL41 is energized. Connected in parallel with RL41 for simultaneous energization thereof is a relay 'RL42 adaptable to open the circuit of round'counter 85 by breaking the continuity of lines H and K at armature 86 The source V2 for energizingthe step-switches in response to the pulse output of the amplifier is connected from the positive terminal +V2 through line F, armature 41 and its a contact (associated with relay RL41 in Fig. 6b), armature 38 and its b contact (when relay RLS is energized in response to a pulse), armature 11 and its a contact, line 41, across terminals a'-a' of push-button P133, and through the winding 70 of relay RL10 to the negative terminal -V2. As relay RL10 is energized in response to each pulse, it attracts armature 71 which enables driving pawl 77 to drive ratchet wheel 80 one step which in turn actuates wipers 87 and 96inunison to move one contact position foreach pulse. One side AC2 of the AC source is connected towiper 96,through line 101. i

While relay'RL10 is in actuable response to the pulse output, the pulse repetition frequency determining network RC1 is connected to oscillator 20. The network RC1 comprises a bank of resistors SR1, which are individually selectable by switch S45, and two banks of condensers, indicated generally as SC1 and comprising a first bank 1C1 and a second bank 1C3 having switches S28 and S27 associated respectively therewith to enable selection of an individual condenser in each bank. Although the resistors in bank SR1 are shown to be fixed resistors, they maybe variable resistors or potentiometers. Switches S28 and S27 are ganged for unicontrol switching. The circuit connecting network RC1 to the oscillator may be traced from resistor bank SR1 through line 115, armature 111 and its a contact, line 110, armature 118 and its a contact, line L to its corresponding line L in Fig. 3, and through one side of switch S7 to oscillator 20, and from the other side of resistor bank SR1 through line 121, armature 112 and its a contact, line 120, armature 119 and its a contact, line L to its corresponding line L in Fig. 3, the other side of switch S7, and through resistor banks R131 and RB2 to oscillator 20. It is to be noted that resistor banks RB1 and RB2 are connected in circuit with the oscillator for both Manual and Auto matic operation, therefore providing additional means, other than network RC1, to adjust the pulse repetition frequency for the Automatic operation of the system. A

The condenser bank 1C1 of network RC1 is traceable from switch S23 through line 123, armature 114 and its a contact, line 105, armature 117 and its a contact, line D to its corresponding line D in Fig. 3, and through one side of switch S5 to grid G1 of oscillator 20, and from the other side of condenser bank 1C1 through line' D to its corresponding line D' in Fig. 3, and through one side of switch S6 to anode A1 of osicllator 20.

The condenser bank 1C3 is connected from one side through switch S27, line 122, armature 113 and its a contact, line 100, armature 116 and its a contact, line C to its corresponding line C in Fig. 3, and through one side of switch S5 to anode A2-of oscillator 20, and from the other side of condenser bank 1C3 through line C to its corresponding line C in Fig. 3, thence through one side of switch S6 to grid G2 of oscillator 20.

As wiper arm 96 is actuated by relay RL11), it moves progressively in single steps from one contact to" a succeeding contact in synchronic correspondence with each pulse in the amplifier output until it engages contact'position 2 where the circuit for relay RL11 is completed from AC2 through line 101, wiper arm 96, contact position 2, selectivemember S15, isolating switch S19, the On terminal, line 81, and through the winding of relay RL11" to AC1, thereby energizing relay RL11.

When relay RL11 is energized, it attracts armatures 9 and 11 to their respective b contacts which supply AC energizing source to relay RLB and the V2 supply voltage to step-switching relay RL20. The AC circuit for RLB is traced from AC1 through line 33, armature 9 and its b contact, line 12, armature 19 and its a contact, line 14, and through the winding of RLB to AC2. Upon being energized, relay RLB pulls armatures 111, 112, 113; and 114 to their b con-tact positions to disconnect frequency determining network RC1 from the oscillator 20 and to couple frequency determining network R02 to os'- cillator 20. The V2 energizing circuit is disconnected from relay RL10 upon relay RL11 being energized and is connected to relay RL20 through armature 11 and its a contact, line 13, armature 21 and its a contact, line 42, across contacts a-a' of push-button PB4, and through winding 70' to the negative terminal -V2. When relay RL11 is energized, it removes the energization from relay RL11), stopping progressive movement of wiper 96 at contact position 2 resulting in relay RL11 remaining energized.

As relay RL20 is energized, itfmoves wiper 97', as-described. heretofore, until wiper. 97 engages contact 3 where relay RL21 is-encrgized from through wiper A 97, contact 3, selective member $16, isolating switch 820s the On terminal, line 82, and through the winding of relay RL21 to AC1. Upon being energized, relay RL21 disconnects the source V2 from 'rela'y RL20, resulting in wiper arm 97 being stopped at contact position 3' and consequently relay RL21 remaining energized, and connects source V2 to step-swi-tch relay RL30 from armature 21 and its b contact through line 18, armature 31 and its a contact, line 43, across contacts a--a of pushbutton PBS, and winding 70" tothe negative terminal --V2; and, at the same time, relay RL21 disconnects the AC source from relay RLB and applies it to relay RLA from armature 19 and its b contact, line 17-, arm's ture 29 and its a contact, line 22, line 95, and the windtraced from resistor bank SR3 through switch S55, line 136, armature 135 and its a contact, line 134, armature 118 and its b contact, and through line L to the oscillator in Fig. 3, and from the other side of resistor bank SR3 through line 137, armature 142 and its a contact, line 138, armature 119 and its b contact, and through line L to the oscillator in Fig. 2. The condenser bank ICS is connected from one side through line C to the oscillator and' from the other side through switch S31, line 130, armature 129 and its a contact, line 128, armature 116 and its b contact, and through line C to the oscillator in Fig. 3. The condenser bank 107 is traced from one side through line D to the oscillator and from the ibithe step-switching relays and to disconnect the selected firing gun from thepulse output of the trigger tube 25, and relay RL42 attracts armature 86 to break the circuit of the round counter, and the system is their red dered incapable of firing a gun or of actuating the stepswitches. I v I v,

Associated with each stepswitch is a light, represented by L1, L2, L3, and L4, and a switch, indicated at S39, S40, S41, and S42, connected to the last terminal of another level of contact positions with which is electri ca-lly associated another wiper, having reference numerals '87, 88, 89, and 90. This associated circuitry con- 'S'titutes the immediate reset circuit and reset circuit indicator of each st'ep-switch. The energizing source for the reset circuit is applied from the positive terminal +V2 through line E, the serially connected contacts, the lower level wiper arms, the self-interrupted armaturecontact, across the b-b contacts of the push-buttons of each step-switch relay, and through the windings of each step-switch relay to the negative terminal -V2& The energizing source for the iridicatoi' circuit is applied from the positive terminal +V1 of source V1 to the light filahieiit, the 1) terminal of the switch connected to q the last contact position, the switch connected to the other side through switch S32, line 133, armature 132 and its a contact, line 131, armature 117 and its b contact, and through line D to the oscillator.

As relay RL30 is energized, it moves wiper 98 to contact position 1 where the energizing circuit for relay RL31 is closed from AC2 through line 103, wiper 98, contact 1, selective member S17, isolating switch S21, the On terminal, line 83, and through the winding RL31 to AC1, resulting in energization of relay RL31.

When relay RL31 is energized, relay RL31 disconnects the V2 sourcefrom relay RL30, stopping wiper arm 98 at contact position 1 and holding relay RL31 energized, and connects the V2 source to step-switch relay RL40 from armature 31 and its b contact, line 44, across contacts a-a' of push-button PB6, and winding 70" to the negative terminal V2; and, at the same time, relay RL31 disconnects the AC source fromvrelay RLA and applies it to relay RL32, which is the holding circuit for relay RLA, from armature 29 and its b contact, lines 26 and 27, and through the winding of relay RL32 to AC2. Whenrelay RL32 is energized, it completes two AC circuit branches from line 26, namely, one branch through armature 144 and its b contact, lines 32 and 95 to relay RLA tomaintain relay RLA energized and holding armatures 116, 117, 118, and 119 engaged to their respective b contacts, and the second branch through armature 143 and its b contact, line 34, and through the winding of relay RLC -to.AC2 to energize relay RLC to attract armatures 135, 142, 129, and 132 to their b contacts thereby connecting frequency determining network RC4 to the oscillator.

As relay RL40 is energized by the pulses, it sweeps wiper 99'in-single steps along the contact positions until Wiper 99 reaches contact position 3 where it completes the energizing'cir'cuit for relays RL41 and RL42 from AC2 through line 104, wiper 99, contact 3, selective mem- 'ber S18, isolating switch S22, the On terminal, lines 109 and 36, and through the windings of relay RL41 and RL42 to AC1. Upon being energized, relay RL41 attracts armatures41tand 42 to open the V2 energizing cirlast contact position when turned to its b contact, the

last contact position of the lower level contact positions, through the switch associated with the lower level contact positions when in engagement with the last contact position, and to the negative terminal -V1. Operation of the gun firing system of Figs. 3, 4, 5, 6a,

and 6b For firing a gun by manual control of the rate of fire of a gun, switch S12 (Fig. 4) is thrown to connect either the electric primed gun or the solenoidally operated gun,

-whichever is desired, switches S8, S9, S10, S11, and

potentiometer R17 (Fig. 3) are adjusted to a desired pulse repetition frequency, switches S2, S5, S6, and S7 (Fig. 3) are switched to the MAN position and oscillator 20 begins to oscillate at a frequency determined by the selected parametric values of the frequency determining circuits RBI, RBZ, CB1, and CB2. The system is now ready to commence firing the selected gun upon depression of firing switch FS.

When firing switch FS is depressed, relays RL1, RL2, 'RL3, and RL4 are energized and attract their respective armatures to connect the output of firing tube 25 to the selected gun whichthen fires a round in response to each pulse at a rate of fire determined by the pulse repetition frequency of the oscillator. As long as the firing switch is held depressed, the gun will continue to fire. If it is desired to change the rate of fire without interrupting the firing of the gun, firing switch FS is maintained depressed and switches S8, S9, S10, S11 and potentiometer R17 are readjusted to another desired pulse repetition frequency. If it is desired to interrupt the firing before changing rates of fire, the firing switch FS is released before the readjustment is made.

For firing a gun automatically through a preselected program of different rates of fire with a preset number of rounds at each rate, the frequency determining circuits RC1, RC2, RC3, and RC4 are adjusted to the pulse repetition frequencies required by the program of different rates of fire, and selective members S15, S16, S17, and S18 of programming switches PS1, PS2, PS3, and PS4, respectively, are set to contact positions corresponding to the number of pulses to be generated at each pulse repetition frequency as required by the number of rounds desired to be fired at each rate of fire.

For purpose of description, it is assumed that selective members S15, S16, S17, and S18 are set as illustrated in Figs. 6a and 6b. In setting the selective members S15, S16, S17, and S18, the utilization or non-utilization of sealers must be taken into consideration. For example,

v 21 ZSQroundsper minuteand no sealer is utilized, then the movable wiper arms 96, 97, 98, and-99 move progressively one contact position for each round fired; if the highest rate of fire in the program exceeds 250 rounds per minute but is less than 500 rounds per minute and a single sealer is used, then the, movable wiper arms 96, 9 7, 98, and99 move progressively one contact position for every two rounds fired by the gun since a single sealer reduces the number of pulses app'liedto relay RL8 to half the number of pulses generated and applied'directly to the gun via trigger tube 25; :and if the highest rate of fire of the program is greater than 500 rounds per minute and less than 1000 rounds per minute and two sealers in cascade are used, then the movable wiper arms move progressively one contact position for every four rounds fired by the gun since two sealers in cascade reduce the number of pulses applied to relay RL8 to onefourth the number of pulses generated and applied directly to the gunby trigger tube 25. Therefore, if no sealers are used, selective members S15, S16, S17, and S18 are set to the contact position corresponding to the number of rounds desired to be fired atteach rate of fire; if a single sealer is used, selective members S15, S16, S17, and S18 are set to the contact position corresponding to one-half of the number of rounds to be fired at each rate of fire; and, if two sealers in cascade are utilized, selective members S15, S16, S17, and S18 are set to the-contact position corresponding to one-fourth the number of rounds to be fired ateaeh rate of fire.

Although the system illustrated in Figs. 3, 4, 5, 6a, and

6b utilizes a sealer, it is to be understood that, if desired,

a switch may be incorporated in the system to by-pass the sealers and connect the pulse output from trigger tube 25 directly to the input of amplifier 50. As a matter of fact, in the following description of the operation of the system it is assumed that no sealer is incorporated in the system, in order to facilitate the description and understanding of the operation of the system.

The frequency determining circuits RC1, RC2, RC3, and RC4 having been adjusted to their desired values and the selective members S15, S16, S17, and S18 having been set to their desired contact positions, switches S2, S5, S6, and S7 are thrown tothe Auto positionand the oscillator commences to generate oscillations at the frequency of determining circuit RC1 to produce pulses in the output of trigger tube at a pulse repetitionfrequency as determined by determining circuit RC1. The :Ystern is now ready to fire the gun upon depression of firing switch FS.

.When firing switch FS is depressed, relays RL1, ,RL2, RL3, and RL4 are energized and attract their respective armatures to close the circuit connecting the trigger tube output at AB to the selected gun, the circuit connecting the trigger tube output across load resistor R8 to'the amplifier 50 (assuming no sealer is used), and the circuit connecting the output of amplifier 55 to the relay R LS, whereupon the gun fires a round in synchronie response to each pulse at a rate of fire determined by the pulse repetition frequency of determining circuit RC1 andrelay RL8 closes the D. C. energizing circuit forthe step-switches and the round counter circuit by drawing armature 38 to its b contact in synehronism with each, amplified pulse appearing in the output of amplifier 55.

As relay RL8 closes the D. C. energizing circuit of V2, step-switch relay RL10 actuates wiper arm 96 until it engages contact position 2 where relay RL11 is energized which in turn energizes relay RLB to disconnect determining circuit RCl from the oscillator and connect determining circuit RC2 to the oscillator and, at the same time,

removes the energizing source' V2 from relay RL10, there by stopping wiper arm 96 at contaet position 2 to maintain relay RL11 in an energized condition, and supplying the energizing source V2 to relay RL20 to actuate .122 wiper-96l Thisproeess eontinuesfrorrr channel tolchannel-until the, entire preset programris fired.

When relay RL41, connected to programming switch PS4, is energized, the V2 energizing source is removed from the step-switching circuit by attracting armature 41 to its b contact and the firing circuit is broken by opening the circuit continuity of lines M and N at armature '42. Also, atflthe same, time, relayRL42 is energized to open the round counter circuit by breaking the circuit continuity of lines H and K at armature 86. Having fired through the program, the firing switch may nowbe released, disconnecting the pulse output from the amplifier (assuming no sealer is used) by opening the armature of relay RL1 and the gun firing circuit by opening the armatures of relay RL3 and RL4, and the amplifier output from relay RL8 by opening the armature of RL2.

To reset the step-switches to the home position, isolating switch S22 and light indicator switch S42 of programming switch PS4 are turned to the Off position and the b terminal, respectively. 'Pushbutton PB6 is depressed, closing the reset energizing circuit 'for relay 'RL40 from the negative terminal -V2 through winding 70, across contacts bb', contacts 60a, contact 60b, wiper arm 90, through the series connected lower level contacts and line E to the positive terminal +V2. Upon relay RL40 being energized, it attracts armature 71" which mechanically drives contact 60a to vbreak with contact Gibb thereby de-energizing relay RL40 causing release of armature 7-1 and returning contact 60a to engage contact 60b. Relay RL40 being of the self-interrupted type, this process will continue as long as push-button PB6is depressed until wiper engages contact where the reset energizing circuit is broken, stopping actuation ofwiper 90 at the contact 150, and the reset indicator circuit is closed from +V1 through the filament of light L4, terminal 11, switch S42, contact 150, wiper 9t), and line 94 to -V1 to light the indicator light L4. Switches S22 and S42 are now returned to their Off position and terminal a, respectively. Since contact 150 and the contact position 0 are degrees apart and .since Wiper arm 90 has two wiper contacts, one at each end, which engage contact 150 and contact position 0 simultaneously, as heretofore described, step-switch SS4 is in the home position. The same procedure is followed for step-switches SS3, SS2, and SS1, in the order named, and'the system is again ready to fire through the same program or a difierent program upon readjustment of the determining circuits RC1, RC2, RC3, andRC4.

If it is desired, all of isolating switches S19, S20, S21, and S22 may be thrown to the Off position before any push-buttons are depressed to the reset position. This procedure is preferable because an accidental depression of firing switch FS will'not' cause the gun to fire due to the fact that relay RL41 is being energized by the-AC source through programming switch PS3 and line 108, programming switch PS2 and line 197, and programming switch PS1 and line106. Push-buttons. PB6, PBS, PB4, and P133, in the order named, are then depressed until step-switches SS4, SS3, SS2, and SS1 are returned to the home position. The isolating switches S19, S20, S21, and S22 are then returned to the On position.

If'scalers are used, the selected gunwill fire a round inresponse to each pulse while the step-switching circuits will be energized on every second or every fourth pulse, depending on whether a single sealer or two sealers, respectively, are connected in the circuit. It is to be understood that any number of sealers may be used, depending on the highest rate of fire in the program of rates of fire. Therefore, the invention provides an electronic gun firing system adaptable to change the rate of fire of a gun manually or to automatically fire a gun through'a preselected program of different rates of fire with a preset number of rounds at each rate. 7

,Obviously many modifications and variations of the 7 present invention are possible. in the light of the above 23 teachings. It-is therefore to be understood, that within the scope of the teachings herein, theinvention may be practiced otherwise than as specifically described.

What is claimed is:

1. A gun firing system comprising, in combination, guns, pulse generating means, gun firing means responsive to the output of said generating means for firing said guns at a rate determined-by the-pulse repetition frequency of said generating means, automatic means for successively varying the pulse repetition frequency of said pulse generating means at predetermined intervals of time to thereby change the rate of fireof said guns in accordance with a preset program of pulse repetition frequency variations, and selective round control means in said means for varying the pulse repetition frequency for selectably determining the number of pulses to be generated at each variation of said program of variations wherebythe number of rounds to be fired at each rate of fire may be selected, said predetermined intervals'of time being determined bythe selected number of pulses to be generated at each variation of said program of variations.

2. A gun firing arrangement comprising, in combination, guns, puls'e'generating means, gun firing means respon'sive to the output of said. pulse generating means for firing said guns ata rate determined by the pulse repeti tion frequency of. said pulse generating means, a plurality of discrete pulse repetition frequency determining circuits, and means for automatically coupling said plurality of determining circuits individually in predetermined sequence to said generating means in accordance with a preset program of sequence to thereby selectably vary the pulse repetition frequency of said generating means through a preselected program of pulse repetition frequencies.

3. In a gun firing arrangement having guns adaptable to be fired by actuating means, actuating means for firing said guns, a plurality of discrete firing rate determin ing means, means in said actuating means for automatically coupling said plurality of determining means individually in predetermined sequence to said actuating means in accordance with a preset program of sequence whereby said guns may be fired through a preselected program of rates of fire, and round control means in said actuating means for selecting in succession in accordance with said preset program of sequence the number of rounds to-be' fired at each firing rate of said plurality.

of discrete firing rate determining means.

4. In an electronic control device for guns, a pulse generator for firing said guns at a rate of fire determined by the pulse repetition frequency of said generating means and comprising, an oscillator, a plurality of discrete oscillator frequency determining circuits, each of said circuits being tuned to a different frequency, manual selective means adaptable to selectably connect individually said determining circuits to said oscillator to thereby enable said oscillator to produce oscillations at a frequency determined by the selected frequency determining circuit connected to said oscillator, and a triggering electron discharge tube coupled to the output of said oscillator and responsive to the oscillations of said oscillator for developing trigger pulses having a pulse repetition frequency determined by the oscillator frequency.

5. In an electronic gun control device having a pulse generator for firing a machine gun in response to the pulse output of said generator at a rate of fire determined by the pulse repetition frequency of said generator, a plurality of adjustable pulse repetition frequency determining circuits, relay means energizably operable at predetermined intervals of time in accordance with a preset program of time intervals to couple at each energization thereof a succedent one of said plurality of determining circuits to said generator whereby the pulse repetition frequency of said generator may be varied through a preselected program of pulse repetition frequenciesto consecutively change the rate of fire of said gun'in accord- 24 time with said preset program of time intervals, aprogrammer having adjustable means for selecting the time intervals of said preset program of time intervals and adaptable to be electrically associated with said relay means to permit energization of said relay means at each ofthe selected time intervals of said presetprogram, and means responsive tothe output of said generator for causing energization of said relay means through said programmer adjustable means at each of the selected intervals of time of said preset program of time intervals to couple a succedent one of said plurality of determining circuits to said generator in accordance with said preset program of time intervals to thereby vary the pulse repetition frequency of said generator through a program of pulse repetition frequencies.

6. A gun firing system comprising, in combination, a gun, a pulse generator having a pulse output for firing said gun at a rate of fire determined by the pulse repetition frequency of said generator and each pulse in the output of said generator firing a round from said gun, a plurality of adjustable pulse repetition frequency determining circuits, relay means energizably operable at predetermined intervals of time in accordance with a preset program of time intervals to couple at each energization thereof a succedent one of said plurality of determining circuits to said generator to therebyvary. the pulse repetition frequency of said generator through a preselected program of pulse repetition frequencies, each of said predetermined. intervals of time of said preset program being determined by the number of pulses desired to be generated at each pulse repetition frequency of said preselected program of pulse repetition frequencies, a programmer, first means in said programmer for selectively determining the number of pulses to be generated at each pulse repetition frequency of said preselected program and correspondingly selecting the time intervals of said preset program, second means in said programmer progressively actuable in responsive concurrence with the pulses at the output of said generator to energize said relay means at each of the selected time intervals of said preset program, and step-switching means responsive to the pulse output of said generator and coupled to said second means for actuating said second means progressively in single steps in concurrence with each pulse of said pulse output to cause said second means to energize said relay means at each 'of the selected time intervals corresponding with the number of pulses selected t'o'be generated and appearing in the output of said generator at each pulse repetition frequency of said preselected program whereupon said relay means operates at each energization thereof to couple a succedent one of said plurality of determining circuits to said generator thereby to vary the pulse repetition frequency of said generator through said preselected program in accordance with said preset program of time intervals whereby the pulse generator generates consecutively through said preselected program the selected number of pulses to be generated at each pulse repetition frequency of said preselected program and consequently firing said gun through a program of different rates of fire with a preset number of rounds at eachrate of fire.

7. A gun firing system as defined in claim 6, further including, a gun firing switch to simultaneously connect the output of said generator. to said gun and to said step-switching means and to initiate the progressive actuation of said second means in said programmer through said preselected program of pulse repetition frequencies in accordance with said preset program of time intervals, and relay operated means responsive to said step-switching means after completion of said preselected program to simultaneously disconnect the gun from said generator output and render said step-switching means inoperable thereby to prevent cyclic repetition of said preselected program.

8-. Agun firing system as defined in claim 7, further including, an electronic scaler intercoupling said gene erator output and said step-switching means for reducing the number of pulses appearing at said output to a submultiple.

9. A gun firing system comprising, in combination, a gun, a pulse generator having a pulse output for firing a round from said gun in synchronism with each pulse in said output at a rate of fire determined by the pulse repetition frequency of said generator, a plurality of adjustable pulse repetition frequency determining circuits adaptable to be successively coupled individually to said generator for predetermined durations of time in accordance with a preset program of time durations whereby the pulse repetition frequency of said generator may be varied through a preselected program of pulse repetition frequencies, the first of said plurality of determining circuits being initially coupled to said generator for permitting said generator to produce pulses at the pulse repetition frequency of said first determining circuit, a relay operated step-switch for each one of said plurality of determining circuits and adaptable to be coupled individually in responsive relation to the output of said generator for a predetermined duration of time corresponding to the predetermined duration of time of its respective determining circuit, each step-switch when in responsive relation with said generator output being actuated by its respective operating relay progressively in single step concurrence in response to each pulse at said pulse output in accordance with the pulse repetition frequency of its respective determining circuit, a programmer having a time duration selective member for each step-switch for determining the time duration each step-switch and its respective determining circuit are to be maintained in responsive relation to said generator output and coupled to said generator, respectively, to thereby provide a preset program of time durations for a preselected program of pulse repetition frequencies, said time durations of said preset program being determined by the number of pulses desired to be generated at each pulse repetition frequency of said preselected program and said desired number of pulses being selected by setting each selective member in a position corresponding to the position its respective step-switch is driven by the desired number of pulses generated at the pulse repetition frequency of its respective determining circuit, said programmer further having a movable member for each selective member and ganged with its respective step-switch for progressive single step movement in unison therewith to ultimately contact its respective selective member in responsive concurrence to the last pulse of the desired number of pulses generated in said generator at the pulse repetition frequency of its respective determining circuit, and a control relay connected to each selective member in said programmer energizably operable when its respective selective member is contacted by its respective movable member to simultaneously decouple its respective pulse repetition frequency determining circuit and its respective step-switch from said generator and said generator output, respectively, and couple the succedent step-switch and the succedent pulse repetition frequency determining circuit to said generator output and said generator, respectively, thereby to vary the pulse repetition frequency of said generator through said preselected program in accordance with said preset program of time durations whereby the generator generates consecutively through said preselected program the selected number of pulses desired to be generated at each pulse repetition frequency of said preselected program and consequently firing said gun through a program of different rates of fire with a preset number of rounds at each rate of fire.

10. A gun firing system as defined in claim 9, further including, a gun firing switch to simultaneously couple said gun and the respective step-switch of said first determining circuit in responsive relation to the output of said generator to initiate the generation of pulses through said preselected program of pulse repetition frequency in accordance with said preset program of time durations, and means responsive to the control relay connected to the last selective member in said programmer to simultaneously decouple the gun from said generator output and decouple the respective step-switch of said last selective member from responsive relation to said generator output to thereby prevent cyclic repetition of said preselected program.

11. A gun firing system as defined in claim 10, further including, an electronic scaler intercoupling said generator output and said relay operated step-switches for reducing the number of pulses at said output to a submultiple.

References Cited in the file of this patent UNITED STATES PATENTS 1,056,602 Steinocher Mar. 18, 1913 1,318,214 Logan Oct. 7, 1919 2,412,632 Sanders Dec. 17, 1946 2,448,024 Golden Aug. 31, 1948 FOREIGN PATENTS 864,373 France Jan. 17, 1941 

